Chitin regulation of immune responses: an old molecule with new roles.
Chitin, the second most abundant polysaccharide in nature, is commonly found in lower organisms such as fungi, crustaceans, and insects, but not in mammals. Although the non-specific anti-viral and anti-tumor activities of chitin/chitin derivatives were described two decades ago, the immunological effects of chitin have been only recently been addressed. Recent studies demonstrated that chitin has complex and size-dependent effects on innate and adaptive immune responses including the ability to recruit and activate innate immune cells and induce cytokine and chemokine production via a variety of cell surface receptors including macrophage mannose receptor, toll-like receptor 2 (TLR-2), and Dectin-1. They also demonstrated adjuvant effects of chitin in allergen-induced type 1 or type 2 inflammation and provided insights into the important roles of chitinases and chitinase-like proteins (C/CLP) in pulmonary inflammation. The status of the field and areas of controversy are highlighted.
Lee
Chun Geun
CG
Section of Pulmonary and Critical Care Medicine, Yale University School of Medicine, 300 Cedar Street (S441 TAC), P.O. Box 208057, New Haven, CT 06520-8057, United States. chungeun.lee@yale.edu
Da Silva
Carla A
CA
Lee
Jae-Young
JY
Hartl
Dominik
D
Elias
Jack A
JA
D000818:Animals; D002686:Chitin / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000276:immunology* / Q000378:metabolism; D004847:Epithelial Cells / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D008262:Macrophage Activation / Q000276:immunology; D011014:Pneumonia / Q000276:immunology; D011956:Receptors, Cell Surface / Q000276:immunology
D016207:Cytokines; D011956:Receptors, Cell Surface; D002686:Chitin; D048271:Chitosan; D002688:Chitinases